Houthi militants ride on a patrol truck at the site of a gathering held by tribesmen loyal to the Houthi movement, in Yemen's capital SanaaReuters

A ceasefire between the Saudi-led coalition and the Shia Houthi rebels has come into effect in Yemen as peace talks between warring factions begin in northern Switzerland.

The week-long truce was postponed by the Saudis, who support the country's internationally recognised government, as pro-government forces took an island in the Red Sea from the Shia militias.

The coalition said it reserves "the right to respond in case of any violation" by the rebels, according to a statement published on SPA state news agency. "The ceasefire will last for a period of seven days from 15-21 December in conjunction with the launch of consultations, and will be renewed automatically in the event of the commitment of the other party".

The seizure of Zuqar Island comes as delegations from Yemen's Houthis, backed by Iran and allies of former president Ali Abdullah Saleh, and the Saudi-led coalition convened in Switzerland.

The coalition backing president Abd-Rabbu Mansour Hadi launched a military campaign to push back the Houthis in March.

Past efforts to end the conflict have failed as the local al-Qaeda franchise and Islamic State (Isis/Daesh) affiliates exploited the chaos in the country to launch attacks and grab territory.

The government has insisted that the Houthis must give up weapons seized from the state and withdraw from territory they have captured in the last year, including the capital Sanaa. The rebels have demanded negotiations over the country's political future.

The truce comes after two coalition officers were reportedly killed near the city of Taiz in Yemen's south-west. Saudi Colonel Abdullah al-Sahyan and Emirate officer Sultan al-Ketbi died "while they were carrying out their duties in supervising operations to liberate Taiz", the official Saudi Press Agency news agency said.

The United Nations says more than 5,800 people have been killed in Yemen, about half of them civilians, since March.